Question

I’m looking for some canonical, simple concurrency problems, suitable for demonstrating usage of a library for concurrent computations I’m working on.

To clarify what I mean by “concurrency”: I’m interested in algorithms that utilize non-deterministic communicating processes, not in e.g. making algorithms like quicksort run faster by spreading the work over multiple processors. This is how I’m using the term.

I know about the Dining Philosophers Problem, and that would be acceptable, but I wonder whether there are any more convincing but equally simple problems.

Answer 1

I generally use a simple “bank account transfer” scenario. For example I posted one such trivial case in this question on transactions.

It’s a good case for exposition because:

• Everyone understands the business problem.
• It emphasises the importances of transactions in a concurrent environment.
• You can easily extend the scenario (e.g. what if you want to calculate the sum of all current account balances while transactions are taking place?)

To demonstrate your concurrency library, you could probably start a thread running millions of transactions in this kind of scenario, and demonstrate how other threads can still see a consistent view of the world etc.